| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed wiring board which allows the developed residues in opening bottoms to be etched off, without roughening the surface, and has a solder resist layer having a constitution superior in heat cycle characteristics. SOLUTION: In a printed wiring board having a solder resist layer on the surface of a wiring board having a conductor circuit, the solder resist layer is composed of an upper layer of a compsn. contg. as a main component a resin composite of a novolak type epoxy resin acrylate and thermoplastic resin and a lower layer of a compsn. prepared by dispersing heat-resistive resin grains soluble to acids or oxidizers in a matrix hardly soluble to acids or oxidizers, contg. as a main component a resin composite of a novolak type epoxy resin acrylate and thermoplastic resin, thus forming a composite layer. |
